what? if you can only go up till GM then consider yourself nub too. Dont bother listening to people that said need group. Let me explain the logic.
Group play is even harder to win unless u get all the pros. When u start to lose often in group play u will then rethink to disband members, not joining their invites etc... Most people in group play are organize or played many many times before and know each other styles/heroes available.

I solo previous x 2 season also can M, last season play lesser coz no time also L. All solo play.

The only time u want to go further is in M with groups of pro for mythical Glory and above..but no point liao la.